1. Field of the Invention
The present invention relates to wireless phones in general and, more particularly, to a method of plumbing wireless phones and the resulting phones thereof.
2. Description of the Related Art
Current wireless phone designs have a radio frequency (RF) clip that carries the RF output from the printed circuit board of the phone. The RF clip contacts the base of the antenna assembly, and RF energy radiates from the entire antenna assembly. Some wireless phones provide shielded transmission paths to the antenna, but the typical design for a wireless phone permits stray RF energy to radiate into free space through unshielded portions of the phone case, especially through a typically unshielded portion of the phone case adjacent to where the RF clip contacts the antenna base. Although this stray RF energy is acceptable for the purposes of the end user, for certain tests and measurements, such as wireless lab measurements, phone characterization data, cell-site optimization measurements, and phone performance verification, the total RF energy produced from the phone transmitter should be confined to the intended transmission path.
FIG. 1 shows a wireless phone 2 which has been modified for the purpose of providing a shielded transmission path to perform various measurements and tests. The phone 2 uses a slip-fit, SMB-type coaxial connector 3 which screws into the antenna base 4. The inside end 6 of the SMB connector 3 is joined to a miniature coax cable 7 that is terminated onto a printed circuit board 8 of the phone 2. The printed circuit board 8 is permanently modified by the installation of the miniature coaxial cable 7. The outside end 9 of the SMB coaxial connector 3 slip fits with a mating coaxial cable assembly (not shown) for performing the various tests and/or performance measurements.
During the modification process, the supplied phone antenna assembly (not shown) is removed and replaced with the SMB connector 3. The RF clip (not shown) is also removed from the printed circuit board 8 of the phone 2, and the miniature coaxial cable 7 is permanently attached to the printed circuit board 8 where the RF clip had been. By removing the RF clip, a discontinuity in the designed characteristics of the transmission path is created. The miniature coaxial cable 7 also causes a discontinuity (impedance mismatches) in the transmission path of the phone 2 because the miniature coaxial cable 7 tends to become folded over and pinched at the fold over site 5. Additionally, the slip-fit SMB connector 3 is mechanically weak and tends to break from phone usage, thereby requiring that the permanently modified phone 2 be thrown away. As such, this process is rather timely, costly, resource dependent and permanently modifies the printed circuit board 8 of the phone 2.
In performing cell-site optimization tests with the SMB-modified phones 2, an expensive shielded box (not shown) has been required to ensure there is no stray RF energy emitting from the phone case 10, especially through a typically unshielded portion 11 of the phone case 10 around where the miniature coaxial cable 7 is connected to the SMB connector 3. The expensive shielded box (not shown) is required because the typical SMB-modified phone 2 still radiates through the case 10, and the miniature coaxial cable 7 is lossy because it radiates RF energy through its braided shield. To perform the cell-site optimization tests, the SMB-modified phone 2 is held by a cradle (not shown) in the shielded box (not shown), and DC power is supplied to the phone 2 through a filtered DC power connection (not shown). The DC power supply and line (not shown) require shielding to protect the integrity of the shielded box (not shown). One end of the small coaxial cable (not shown) is connected to the outside end 9 of the SMB connector 3, and the other end of the small coaxial cable (not shown) is connected to one end of a SMA-type RF bulkhead connector (not shown). The RF bulkhead connector (not shown) passes through the metal wall of the shielded box (not shown), and the other end of the RF bulkhead connector is joined to another coaxial cable (not shown) leading to an antenna (not shown) mounted on a vehicle (not shown) which is driven around to perform the cell-site optimization tests. The use of the expensive shielded box (not shown) is not only costly but cumbersome and time consuming as well. For example, the phone 2 has to be mounted within the shielded box (not shown), and the shielded box (not shown) must be carried to and from the vehicle in which the tests are typically performed. Additionally, the phone 2 is inaccessible while it is in the shielded box (not shown).
Accordingly, a need exists for an enhanced and cost effective system for converting wireless phones that radiate stray RF energy into wireless phones which confine the RF energy to the shielded transmission path.